Protein trafficking to the plastid of Plasmodium falciparum is via the secretory pathway
Protein trafficking to the plastid of Plasmodium falciparum is via the secretory pathway
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DOI：
10.1093/emboj/19.8.1794
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发表时间：
2000-04-17
期刊：
影响因子：
11.4
通讯作者：
McFadden, GI
中科院分区：
文献类型：
--
作者：
Waller, RF;Reed, MB;McFadden, GI
恶性疟原虫的质体（或“顶质体”）是植物叶绿体的进化同源物，代表了光合作用过去的遗迹。顶质体的不可或缺性表明它仍然为寄生虫提供必要的功能。与植物叶绿体类似，顶质体依赖于许多核编码基因来提供这些功能。顶质体由四层膜包围，比植物叶绿体多两层。因此，靶向顶质体的蛋白质必须克服额外的膜屏障。在恶性疟原虫中，我们使用绿色荧光蛋白（GFP）分析了顶质体靶向。我们证明，蛋白质靶向至少是一个两步的过程介导的二分N-末端前序列，包括信号肽进入分泌途径和植物样转运肽随后进口到顶质体。与其它已知的质体转运肽相比，恶性疟原虫转运肽不需要丝氨酸或苏氨酸残基。在顶质体靶向过程中逐步去除前序列组分。针对绿色荧光蛋白的apicoplast也提供了第一次机会，检查apicoplast形态活恶性疟原虫。
The plastid of Plasmodium falciparum (or 'apicoplast') is the evolutionary homolog of the plant chloroplast and represents a vestige of a photosynthetic past. Apicoplast indispensability indicates that it still provides essential functions to parasites. Similar to plant chloroplasts, the apicoplast is dependent on many nucleus-encoded genes to provide these functions. The apicoplast is surrounded by four membranes, two more than plant chloroplasts. Thus, protein targeting to the apicoplast must overcome additional membrane barriers. In P.falciparum we have analyzed apicoplast targeting using green fluorescent protein (GFP). We demonstrate that protein targeting is at least a two-step process mediated by bipartite N-terminal presequences that consist of a signal peptide for entry into the secretory pathway and a plant-like transit peptide for subsequent import into the apicoplast. The P.falciparum transit peptide is exceptional compared with other known plastid transit peptides in not requiring serine or threonine residues. The presequence components are removed stepwise during apicoplast targeting. Targeting GFP to the apicoplast has also provided the first opportunity to examine apicoplast morphology in live P.falciparum.